I found many pages on the Internet that might be helpful for you.
This might be good for information about both precious metal catalysts recovery and refining: http://sabinmetal.com/2013/catalyst-recovery/
This page goes into detail about precious metal catalysts recovery and refining. It explains what catalysts are, the catalyst recovery, precious metal recovery, refining, and types of sampling. As you can see, this page gives you an overview of how metals are recovered and what they go through to have impurities removed.
This might be helpful for information about refining: http://www.simsrecycling.com/Services/R ... s/Refining
There is a video at the bottom of the page that shows how a company called Sims Recycling Solutions recovers precious metals.
On Science Buddies, there is an article that gives you tips on how to find information for a research paper: https://www.sciencebuddies.org/science- ... nformation
You could also try to find more information by typing "Precious Metal Catalysts Recovery and Refining", "How are precious metals refined?", and "Catalyst Recovery" on the search engine.
I hope this helps you to find more information on precious metal catalysts recovery and refining. If you have any additional questions, please let us know.